Cu, Co, Ni nanoparticles supported ceria catalysts in ambient pressure CO2 hydrogenation

A series of CeO2 supported Cu, Co, and Ni catalysts have been synthesized by the wetimpregnation method for CO2 thermo-catalytic hydrogenation from 200 – 400 °C in the fixed bed reactor. All catalysts were characterized by XRD, N2-isotherms, and H2 temperatureprogrammed reduction. XRD results have suggested that the incorporated Cu, Co, and Ni have uniformly distributed on the CeO2 surface, N2-isotherm analysis confirmed that the pores of CeO2 were blocked by incorporated metals and H2-TPR indicated strong interaction between active metal and CeO2. The CO2 consumption rate and product selectivity depend on the type of active metal on CeO2 and reaction temperature. The order of CO2 consumption rate for 5wt% catalysts was 5Ni/CeO2 > 5Co/CeO2 > 5Cu/CeO2 at 400 °C. The high CO2 consumption rate for 5Ni/CeO2 was attributed to the presence of more number of active metallic Ni during the reaction which dissociated H2 molecule to H-atoms. The formed H-atoms reacted with active CO2 molecule and formed CH4 with 100% selectivity

FOTONAPONSKI SUSTAVI S OBJE STRANE RIJEKE DRAVE

The aim of present study is to review the introduction of solar energy utilization, the economic determination of the return of crystalline solar systems in Hungary and in Croatia on the two banks of Drava River. The authors have calculated with the electricity price reductions for individuals in Hungary also, which gives more interest to this article. The study was performed with crystalline solar systems and it was carried out in solar-electric power plants extended from 1.5 kWp to 10 kWp. The study included the investment of crystalline solar cell systems. The calculation of payback time was performed by dynamic indices.Cilj je sadašnje studije razmotriti postojeće stanje iskorištenja sunčeve energije i gospodarske razloge za povratak solarnih panela u Mađarskoj i Hrvatskoj na obje obale rijeke Drave. Autori su računali i na smanjenje cijene struje u Mađarskoj za domaćinstva, što povećava interes za ovaj rad. Studija je provedena na energanama sa solarnim panelima, snage od 1.5 - 10 kWp. U istraživanje je uključena vrijednost investicije nabave solarnih sustava. Izračun povrata uloženih sredstava proveden je korištenjem dinamičkih indeksa

Combining plasma phospho-tau and accessible measures to evaluate progression to Alzheimer’s dementia in mild cognitive impairment patients

BACKGROUND: Up to now, there are no clinically available minimally invasive biomarkers to accurately identify mild cognitive impairment (MCI) patients who are at greater risk to progress to Alzheimer's disease (AD) dementia. The recent advent of blood-based markers opens the door for more accessible biomarkers. We aimed to identify which combinations of AD related plasma biomarkers and other easily accessible assessments best predict progression to AD dementia in patients with mild cognitive impairment (MCI). METHODS: We included patients with amnestic MCI (n = 110) followed prospectively over 3 years to assess clinical status. Baseline plasma biomarkers (amyloid-β 42/40, phosphorylated tau217 [p-tau217], neurofilament light and glial fibrillary acidic protein), hippocampal volume, APOE genotype, and cognitive tests were available. Logistic regressions with conversion to amyloid-positive AD dementia within 3 years as outcome was used to evaluate the performance of different biomarkers measured at baseline, used alone or in combination. The first analyses included only the plasma biomarkers to determine the ones most related to AD dementia conversion. Second, hippocampal volume, APOE genotype and a brief cognitive composite score (mPACC) were combined with the best plasma biomarker. RESULTS: Of all plasma biomarker combinations, p-tau217 alone had the best performance for discriminating progression to AD dementia vs all other combinations (AUC 0.84, 95% CI 0.75-0.93). Next, combining p-tau217 with hippocampal volume, cognition, and APOE genotype provided the best discrimination between MCI progressors vs. non-progressors (AUC 0.89, 0.82-0.95). Across the few best models combining different markers, p-tau217 and cognition were consistently the main contributors. The most parsimonious model including p-tau217 and cognition had a similar model fit, but a slightly lower AUC (0.87, 0.79-0.95, p = 0.07). CONCLUSION: We identified that combining plasma p-tau217 and a brief cognitive composite score was strongly related to greater risk of progression to AD dementia in MCI patients, suggesting that these measures could be key components of future prognostic algorithms for early AD. TRIAL REGISTRATION: NCT01028053 , registered December 9, 2009

Study of the composition and size distribution of gold-containing bimetallic nanoparticles synthesized in a spark discharge generator

Nanotechnology is one of the most dynamically growing fields of science, which requires the production of engineered nanoparticles (ENP) for various applications. Chemical synthesis procedures were dominating the field for many years, but physical procedures, that are based on laser or discharge ablation, are becoming more and more popular nowadays. One of these ablation-based methods is spark discharge generation, which is a versatile method for the preparation of mono- or bimetallic nanoparticles. In a spark discharge generator (SDG), a high voltage oscillating discharge is produced between two electrodes made of at least moderately conducting material. The erosion of the electrodes produce an atomic vapor in the spark gap, which is carried away by a gas flow. Nucleation and coagulation processes lead to nano-sized aggregates, which are then compacted to form spherical nanoparticles (NP). This method produces high purity NPs. SDGs can also be run continuously, thus industrial rate production is also possible. Control of the particle properties (e.g. concentration and size) can be achieved by tuning the operating conditions of the generator. The SDG method can also be considered cost-efficient and environmentally friendly. The goal of the present work was to study how the operating parameters of SDGs influence the composition and size distribution NPs in the case of certain bimetallic particles (BNPs). In particular, we intended to study the influence of the electrode polarity, gap size and compaction on Au-Ag and Au-W particles

Turning CO2 to CH4 and CO over CeO2 and MCF-17 supported Pt, Ru and Rh nanoclusters – Influence of nanostructure morphology, supporting materials and operating conditions

Efficient conversion of CO2 into CH4 and CO brings an important opportunity to get valuable feedstock for a variety of industrially important reactions as both CH4 and CO are widely used as starting materials for the synthesis of valuable fuels and chemicals. Herein, we synthesized sub-nanometer (<2nm) Platinum (Pt), Ruthenium (Ru) and Rhodium (Rh) nanoclusters (NCs) via colloidal method; successfully decorated over mesoporous CeO2 and high surface area (HSA) siliceous meso-cellular foam (MCF 17) and tested for high-pressure CO2 reduction at lower temperature range (220–340 ◦C). Pt and Ru NCs exhibited typical reverse water gas shift (RWGS) and methanation catalytic performance respectively with minimal influence of the nature of support however, Rh NCs showed drastic variations in the product selectivity which exhibited strong influence of the support over the product distribution. Furthermore, Ru NCs (with a relatively lower metal loading ~ 1 wt %) were found to be highly selective to CH4 (~99 %) and stable (upto 40 hr time on stream) with either CeO2/MCF 17 at 340 ◦C; also Ru NCs exhibited comparatively the highest CO2 conversion (~93 % in case of Ru NCs/CeO2) among the supported metal NCs. HRTEM results showed that metal NCs were homogeneously dispersed with a controlled and uniform particle size (<2nm); no substantial agglomeration of Ru NCs were observed after reaction. Beside the stable dispersion of NCs, Near Ambient Pressure (NAP) in situ XPS of Ru/CeO2 showed that the dynamic Ce3+/Ce4+ ratio of CeO2 can attribute to the high activity and selectivity

Phosphorus-loaded alumina supported nickel catalysts for CO2 hydrogenation: Ni2P/Ni5P12 drives activity

A series of 5 wt% NiO-xP-Al2O3 with different phosphorus loading contents (x = 0, 5, 15 and 20 wt%) were prepared by a modified sol-gel method. A significant promotional effect of phosphorus on NiO-Al2O3 in CO2 hydrogenation is observed. All the catalysts reach the highest conversion at 600 °C with 61.54 %, 62.89 %, 63.88 % and 66.13 % respectively for 5 wt% NiO-Al2O3, 5 wt% NiO-5P-Al2O3, 5 wt% NiO-15P-Al2O3 and 5 wt% NiO20P-Al2O3 catalysts. Ni/NiO/Ni2P/Ni5P12/AlPO4 interfacial species were detected on the surface as active species on the used catalysts by X-ray photoelectron spectroscopy. The formation ratio of the metal-phosphide is relatively low ∼3−5 %, and this atomic concentration is decreasing with the rising of the phosphate content. However, the nickel enrichment in the surface layer presumable in Ni2P/Ni5P12 form is very likely according to the P 2p spectra and the authors assume that could be responsible for the enhanced catalytic activity

Экспериментальное исследование процесса влагоудаления из различных типов древесной хвойной биомассы при подготовке к получению тепловой энергии.

В результате эксперимента получены результаты изменения массовой скорости испарения, коэффициента аккомодации и парциального давления для хвойных пород древесины. Получены зависимости массовой скорости испарения от температуры, массовой скорости испарения от времени испарения, а также проведен расчет коэффициента аккомодации.As a result of the experiment, the results of changes in the mass evaporation rate, accommodation coefficient and partial pressure for coniferous wood species were obtained. Dependences of the mass evaporation rate on temperature, mass evaporation rate on evaporation time, and calculation of the accommodation coefficient are obtained